This invention relates to stage devices, exposure apparatus, and methods of manufacturing devices, and more specifically to stage devices provided with a supporting plate and a slider that moves along the supporting plate, exposure apparatus provided with such a stage device, and methods of manufacturing devices using the exposure apparatus.
Recently, in a lithographic process that manufactures a semiconductor element, a liquid crystal display element, etc., a step-and-scan type scanning exposure apparatus (so-called scanning stepper (scanner)) often is used that synchronously moves a mask or a reticle (hereafter referred to as “reticle”) and a photosensitive object such as a wafer or a glass plate (hereafter referred to as “wafer”) along a predetermined scanning direction (scan direction) and transfers a reticle pattern onto the wafer via a projection optical system. A scanning exposure apparatus can expose a large field with a projection optical system smaller than a stationary type exposure apparatus such as a stepper. Because of this, there are various advantages associated with a scanning exposure apparatus, e.g., manufacturing of a projection optical system is easier, high throughput is expected due to the reduction of the number of shots by large field exposure, averaging effects can be obtained by scanning a reticle and a substrate relative to a projection optical system, and distortion and depth of focus can be improved.
Therefore, in a scanning exposure apparatus, a drive device is needed that drives a reticle on the reticle side in addition to the wafer side. In recent scanning exposure apparatus, as a drive device on the reticle side, a reticle stage device with a coarse/micro-moving structure is used that has a reticle coarse-moving stage that is floatingly supported on a reticle supporting plate by an air bearing or the like and is driven in a scanning direction within a predetermined stroke range by a pair of linear motors arranged on both sides in a non-scanning direction perpendicular to a scanning direction, and a reticle micro-moving stage that is micro-moved in a scanning direction, a non-scanning direction, and a yawing direction by a voice coil motor or the like with respect to the reticle coarse-moving stage.
Furthermore, there also is a reticle stage device in which, in order to suppress the vibration and attitude fluctuation of a reticle support plate that are caused by a reaction force generated in a stator of a linear motor according to driving of a reticle stage, a countermass mechanism is arranged that has a countermass (weight member) that, upon receiving the reaction force, moves according to the law of conservation of momentum, e.g., in a direction opposite to the reticle stage along with a stator (linear guide) of a linear motor that extends in a scanning direction of the reticle stage.
However, in a reticle stage device used by a conventional scanning exposure apparatus, there are various points that need to be improved as follows:
a. There is a side guide between a supporting plate and a stator carrier that mounts the motor stator for driving the micro-moving stage. Therefore a reaction and a yawing moment at the time of positioning the reticle micro-moving stage (reticle) in a non-scanning direction, and a moment generated at the time of driving the coarse-moving stage, are transmitted to the supporting plate via the side guide, which causes vibration of the supporting plate. As a result, accurate position control (including positioning accuracy) of the reticle is deteriorated.
b. Wiring for supplying an electric current, piping for vacuum exhaust for a vacuum chuck, piping for supplying pressurized air for an air bearing, etc. were connected to the reticle-micro-moving stage and the reticle coarse-moving stage. Because of this, when the reticle micro-moving stage and the reticle coarse-moving stage were moved, the above-mentioned wiring and piping were dragged, and the tension of the wiring and the piping ultimately caused accurate position control (positioning accuracy) of the reticle to deteriorate.
c. Mechanical vibration near the reticle micro-moving stage and stage distortion due to heat caused positional measuring errors of the reticle micro-moving stage. As an example, as shown in FIG. 12A, a case is considered in which the position of a reticle micro-moving stage RST (reticle R) is measured by an interferometer having a length measurement axis LX via a moving mirror 169 arranged on the reticle micro-moving stage RST. In this case, if distortion shown in FIG. 12B is generated on the reticle stage RST, the ΔM measuring error (a type of Abbe number) is generated in positional information to be measured by the interferometer. In addition, in FIGS. 12A and 12B, symbol CR shows a neutral plane (curved neutral plane) of the reticle micro-moving stage RST.
d. Furthermore, the distortion of the reticle micro-moving stage caused the distortion (curving) of the moving mirror, and accurate position measurement of the reticle micro-moving stage, and in turn, accurate position control was deteriorated.
e. Furthermore, particularly in a reticle stage device provided with a countermass mechanism, it was difficult to maintain a sufficiently large mass ratio of a countermass (weight member) and a reticle stage. This is because in the above-mentioned conventional countermass mechanism, the countermass needs to have its center of gravity arranged on an axis of a linear guide. Thus, in order to increase the countermass weight, the countermass needs to be extended in an axial direction of the linear guide, or its dimension in a radial direction within an axially perpendicular plane about the linear guide needs to be uniformly increased, so there is naturally a restriction in terms of layout. Thus, it was difficult to sufficiently obtain a mass ratio of the countermass (weight member) and the reticle stage, so the stroke of the countermass became large, effects due to dragging the piping and local body distortion due to center of gravity movement could not be ignored, and therefore position controllability deteriorated.
f. In addition, the arrangement and the shape of the members near the reticle stage were complex, and the surrounding space was a complex open space. Thus, air adjusting efficiency was poor, accurate interferometer measurement, and in turn, the reticle position controllability, deteriorated due to air fluctuation (air temperature fluctuation), etc. Furthermore, when vacuum ultraviolet light such as an F2 laser is used as exposure illumination light, a gas purge must be performed in the vicinity of the reticle (and at other locations) that replaces an atmospheric gas with an inert gas. However, the above-mentioned arrangement and shape of the members near the reticle stage were complex, so the design was extremely difficult.